Quality Control Assessment and Biodistribution of Indigenously Developed [99mTc]DTPA-bis(ChoEA) During Initial Clinical Assessment as a Potential Imaging Agent for Prostate Cancer

Introduction: SPECT and PET radiopharmaceuticals have been used in early diagnosis of prostate cancer. C-11 methionine is a PET tracer but it is expensive and not widely available in many centres. SPECT-based tracer [99mTc] DTPA-bis (ChoEA) has shown promising results with brain tumor imaging. The uptake of [99mTc] DTPA-bis (ChoEA) is facilitated by the up-regulation of amino acid transporters which has been observed in many tumor cells to facilitate these accelerated rates of amino acid uptake. It is readily available at low cost and could possibly have potential for detection of prostate cancer. Aim of the study: To assess quality control and biodistribution of indigenously developed [99mTc] DTPA-bis (ChoEA) during initial clinical assessment in patients with prostate cancer. Objectives of the study: To study the physiological uptake of radiolabeled amino acids [99mTc]DTPA-bis(ChoEA) in patients with known carcinoma prostate and evaluate the labelling efficiency of indigenously prepared [99mTc]DTPA-bis(ChoEA) kits. Results: A total of 15 patients were included in our study. Physiological uptake of tracer [99mTc]DTPA-bis(ChoEA) was seen in liver, kidneys and blood pool in visual inspection. The tracer uptake was maximum at 1 hour and gradually reduces over next 3 hours. A total of 15 patients with carcinoma prostate were available for evaluation with [99mTc]DTPA-bis(ChoEA). This showed significant choline biodistribution at 1hr with mean liver uptake: Bkg (background) ratio of (7.7± 2.97) & kidney uptake: Bkg ratio of (6.6±0.14) in whole body imaging. Biodistribution of this tracer and its labelling efficiency on the scans was found to be satisfactory in all patients. Conclusion: This is the first study done for assessment of [99mTc]DTPA-bis(ChoEA) in patients with prostate cancer. The radiochemical purity of 99mTc- choline was nearly ~97% which was in the acceptable range with physiological tracer uptake was seen in kidneys, liver and blood pool.